Thermoplastic coating compositions and process using same

ABSTRACT

This invention provides for a coating composition comprising: (A) at least one polymeric material selected from (i) at least one homopolymer of ethylene having a melt index of at least about 220 grams per ten minutes as determined by ASTM D1238, condition 190/2.16, or (ii) at least one copolymer of ethylene and a second ethylenically unsaturated monomer having a melt index of at least about 20 grams per ten minutes as determined by ASTM D1238, condition 190/2.16, or (iii) at least one thermoplastic acrylic homopolymer or copolymer having a glass transition temperature (Tg) of greater than 0° C. but less than 110° C., or (iv) a mixture of (i), (ii) and/or (iii); and (B) at least one thermoplastic polymeric material different than (A) having a melting point in the range of about 80° C. to about 130° C. and being miscible with (A) and wherein the viscosity of the polymer composition (A) and (B) is in the range of about 5,000 cps to about 100,000 cps at a temperature range of about 200° F. to about 300° F. The invention further provides for a process for applying the foregoing coating composition to a substrate such as glass, ceramic, metal, fiberboard, textile or plastic substrate (e.g., glass jars or bottles) preferably using hot melt screen printing; the process employs a low-temperature cure that requires only a relatively brief cure time (e.g., less than about one second). The coating composition can be reheated to obtain higher gloss and/or enhance the adhesion of the coating to the substrate.

RELATED APPLICATIONS

This application is a continuation of application Ser. No. 07/705,638filed May 22, 1991, now abandoned, which is a continuation-in-part ofapplication Ser. No. 07/418,399 filed Oct. 6, 1989 which issued as U.S.Pat. No. 5,202,162.

TECHNICAL FIELD

This invention relates to thermoplastic coating compositions and toscreen processes using said compositions.

BACKGROUND OF THE INVENTION

The decoration of ceramic surfaces by the so-called silk screen processis well established. A screen of fine metal wires is used in whichselected areas of the screen are blocked or masked so as to pass throughthe screen a decorating ink or paint in a predetermined pattern only,the pattern defining the print to be deposited on the ceramic. Thispractice has encountered a number of problems arising in particular withthe demands of ever increasing speed in screen application, multi-colorscreen printing, and economic considerations in screen-printingdisposable or throwaway containers.

For many years screen printing of glass such as glass enamel, has beencarried out by dispersing a pigment and ground vitreous frit in a liquidvehicle, such as a viscous oil, squeegeeing the dispersion through amasked screen onto the glass surface, and then firing the glass to driveoff the organic constituents of the dispersion and fix the pigment tothe glass surface. When the speed requirements of screen printing arenot great and/or highly durable, fired prints are desired, this processis quite satisfactory. There are disadvantages with this process,however, when multi-color, superimposed or adjoining prints are desired.In these cases, each screening operation must be followed by air-dryingand hardening steps, often involving oven equipment, before a succeedingscreen application can be made on the same glass ware, followed in turnby still additional drying prior to screen application of another color,etc., in order to prevent smearing and blending of one color intoanother before the ware is ultimately fired at a relatively hightemperature, for example, 1200° F.

To eliminate the necessity for a drying operation after each screenprinting, particularly in multi-color applications, hot melt orthermo-fluid ceramic inks have been developed. These inks typicallycomprise a thermoplastic vehicle and a glass binder. They are solid atthe temperature of the ware to be printed (normally room temperature)and become fluid and therefore flowable when heated to a highertemperature. In the fluid condition, thermo-fluid ceramic inks areforced through a screen in the usual manner onto a substrate to beprinted where they solidify almost instantly because of the relativelylow temperature of that substrate. These inks may be maintained in afluid condition either by radiant heat or by passing an electric currentthrough the wires of the screen.

In order to function properly, such thermo-fluid ceramic inks must havecertain physical properties. Thermo-fluid ceramic inks must melt quicklywithin a narrow temperature range without substantial physical orchemical change; they must not run after application to a surface; andthey must level properly before solidifying. If the thermo-fluid ceramicink has insufficient fluidity, tiny pinholes result in the design leftby the screening operation. The pinholes later enlarge during a firingoperation and permanently detract from the appearance of the printeddesign. Pinholes also tend to promote bleeding of subsequently screenedcolors into other colors during the time required for the subsequentlyscreened colors to solidify.

Other requirements for a satisfactory thermo-fluid ceramic ink includegood adherence to ceramic, metal or glass surfaces; avoidance ofgelation when in a molten condition; stability over prolonged periods oftime; moisture-resistance; ability to be fired without leavingobjectionable carbon deposits; and, where required, the ability to meetvarious hot alkali tests.

In view of these essential and sometimes diverse specifications,difficulty has been met in producing thermo-fluid ceramic inks that meetall these requirements and that are uniformly suitable for variousscreen applications. Previously, the art has found it necessary tocompound thermo-fluid inks from a fairly large number of components inorder that the inks have as many as possible of the listed desiredphysical properties. One or more natural waxes in combination with oneor more natural resins in combination with still other ingredients havebeen suggested. For example, U.S. Pat. No. 2,748,093 discloses a vehiclesuitable for the application of enamel by a screen process, the vehiclecomprising diphenyl, hydrogenated rosin, an ethylene glycol ester ofhydrogenated rosin, a diethylene glycol ester of hydrogenated rosin, andpolybutene. U.S. Pat. No. 2,807,555 discloses a thermo-fluid vehiclecomprising a mixture of the reaction product of stearic acid and analiphatic amine, a natural vegetable wax, polyethylene glycol, andoptionally a phosphorated tall oil. U.S. Pat. No. 2,842,454 discloses athermo-fluid vehicle comprising paraffin, natural vegetable wax andaluminum stearate.

The use of known thermo-fluid ceramic inks has not always achievedentirely satisfactory results in multicolor screen printing because ofdamage to previous prints from the heat of succeeding screenapplications. For example, screen markings from one screen applicationcan appear on the print of a preceding screen application. Oralternatively, a succeeding screen application can pick-off or lift-offpart of the print of a previous screen application.

Moreover, the increasing use of disposable, nonreturnable containers hasintroduced a further cost consideration. In addition to the foregoingrequirements, an ink used for screen printing, either for single ormulticolor printing, must also be relatively inexpensive for applicationto containers designed to be thrown away after a single use.

It is known to use a thermo-fluid ink containing a low-densitypolyethylene having a melt index of 200 grams per ten minutes asdetermined by ASTM D1238, a polyterpene resin, wax, pigment and fillersto decorate a plastic substrate.

U.S. Pat. No. 3,872,044 discloses thermo-fluid ink adapted forapplication by a screen process to ceramic, metal or plastic ware, theink comprising a solid thermoplastic polyamide resin formed by reactinga dicarboxylic acid, such as a dimerized fatty acid, with a lineardiamine such as hexylmethyldiamine. The solid polyamide has a molecularweight or can be plasticized with a sufficient amount of a compatibleplasticizer to have a melting point within the range of about 85° C. toabout 120° C. The ink also includes a sufficient amount of a pigment toimpart color or opacity, and can include an organo silane.

SUMMARY OF THE INVENTION

This invention provides for a printable coating composition for forminga decorative coating on substrate comprising: (A)(i) at least onehomopolymer of ethylene having a melt index of at least about 220 gramsper ten minutes as determined by ASTM D1238, condition 190/2.16, or (ii)at least one copolymer of ethylene and a second ethylenicallyunsaturated monomer having a melt index of at least about 20 grams perten minutes as determined by ASTM D1238, condition 190/2.16, or (iii) atleast one thermoplastic acrylic homopolymer or copolymer having a glasstransition temperature (Tg) of greater than OeC but less than 110° C.,or (iv) a mixture of (i), (ii) or (iii); and (B) at least onethermoplastic polymeric material different than (A) having a meltingpoint in the range of about 0° C. to about 130° C. and being dispersiblewith (A) wherein the polymer composition of (A) and (B) is normallysolid at room temperature but is a viscous liquid at about 200° F. toabout 300° F. with a viscosity in the range of about 5,000 cps to about100,000 cps. At least one of the (A) polymeric materials should becapable of melt flow upon heating.

The invention further provides for a process for applying the foregoingcoating composition to a substrate and the resultant coated articlessuch as glass, ceramic, metal, fiberboard, textile or plastic (e.g.,glass jars or bottles) preferably using hot melt screen printing; theprocess employs a low-temperature cure that requires only a relativelybrief cure time (e.g., less than about one second). Specifically, theprocess comprises:

(1) heating the composition of claim 1 to a temperature in the range ofabout 70° C. to about 135° C.; and

(2) applying said composition to said substrate.

The coating composition can be reheated to obtain higher gloss and/orenhance the adhesion of the coating to the substrate. Moreover, thecoating composition of the present invention may be substantiallysolvent-free and thus avoid the handling, processing and environmentalproblems associated with commercial coatings and inks which require asolvent.

Still further according to the present invention, a printable,substantially solvent-free coating composition for forming a decorativecoating on a substrate is provided and comprises:

(A) at least one copolymer of ethylene and a second ethylenicallyunsaturated monomer having a melt index of at least about 20 grams perten minutes as determined by ASTM D-1238, condition 190/2.16; and

(B) at least one thermoplastic polymeric material different than (A)having a melting point in the range of about 80° C. to about 130° C. andbeing miscible with (A).

Still further according to the present invention, a printable,substantially solvent-free coating composition for forming a decorativecoating on a substrate is provided and comprises:

(A) at least one thermoplastic acrylic copolymer having a glasstransition temperature (Tg) of greater than 10° C. but less than 110°C., and

(B) at least one thermoplastic polymeric material different than (A)having a melting point in the range of about 80° C. to about 130° C. andbeing miscible with (A).

Still further according to the present invention, a printable,substantially solvent-free coating for forming a decorative coatingcomposition on a substrate is provided and comprises:

(A) at least one ethylene-vinyl acetate copolymer having a melt index ofat least about 20 grams per ten minutes as determined by ASTM D-1238,condition 190/2.16, and a vinyl acetate content in the range of up toabout 60% by weight; and

(B) at least one polyterpene or aromatic modified polyterpene having amelting point in the range of about 80° C. to about 130° C.

In summary, applicants' invention resides in developing a specificformulation of very specific components having specific physicalproperties to provide a printable, e.g., silk screenable, coatingcomposition for specific substrates that overcomes the problems of thecoatings now being used in the industry and provides coatings havingproperties and applicability which has not yet been achieved in the art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The inventive coating compositions may be referred to as hot meltpolymer decorations. The coatings of the present invention may beprotective to the substrate as well as decorative. In addition to thehomopolymer or copolymer (A) and the thermoplastic polymeric material(B), referred to above, these coating compositions can optionallyinclude one or more pigments (C), waxes (D), silicone polymers (E),fluorocarbons (F), plasticizers (G), surfactants (H), organosilanes (I),adhesion promoters (J) and dyes and/or fillers.

The polyethylene homopolymers (A)(i) preferably have melt indexes of atleast about 220 grams per ten minutes as determined by ASTM D1238,condition 190/2.16. The melt indexes for these homopolymers are morepreferably in the range of about 250 to about 2500, and more preferablyabout 250 to about 500, more preferably about 300 to about 400 grams perten minutes as determined by the foregoing ASTM test method. Thesehomopolymers preferably have densities in the range of about 0.90 toabout 0.96 gms/cc. Examples of commercially available polyethylenehomopolymers that are useful include Petrothene NA601-00/04 (a productof Quantum Chemical identified as a polyethylene homopolymer having amelt index of 2000 grams per ten minutes as determined by ASTM D1238,condition 190/2.16, and a density of 0.903 gms/cc), and PetrotheneNA598-00 (a product of Quantum Chemical identified as a polyethylenehomopolymer having a melt index of 400 grams per ten minutes asdetermined by ASTM D1238, condition 190/2.16, and a density of 0.916gms/cc).

The copolymers (A)(ii) that are preferred include copolymers of ethylenewith vinyl acetate, methyl acrylate, ethyl acrylate, butyl acetate,acrylic acid, methacrylic acid, and metal salts of acrylic acid andmethacrylic acid. These copolymers preferably have melt indexes of atleast about 20 grams per ten minutes as determined by ASTM D1238,condition 190/2.16. The melt indexes for these copolymers are morepreferably in the range of about 20 to about 2500, more preferably about20 to about 500 grams per ten minutes as determined by the foregoingASTM test method. These copolymers preferably have densities in therange of about 0.90 to about 0.96 gms/cc.

The ethylene-vinyl acetate copolymers (A)(ii) that are useful with theinventive coating compositions have a vinyl acetate contents thatpreferably range up to about 60% by weight, more preferably about 5% toabout 60% by weight, more preferably about 5% to about 52% by weight,more preferably about 25% to about 35% by weight. In one embodiment ofthe invention copolymers having vinyl acetate contents preferably in therange of about 6% to about 40% by weight are useful. In anotherembodiment, copolymers having vinyl acetate contents in the range ofabout 40% to about 52% by weight are useful. The melt index ispreferably at least about 20 grams per ten minutes, more preferablyabout 20 to about 2500 grams per ten minutes, more preferably about 20to about 500 grams per ten minutes. In one embodiment of the inventionthe melt index is in the range of about 20 to about 200 grams per tenminutes. In another embodiment the melt index is in the range of about300 to about 400 grams per ten minutes. In another embodiment, mixturesof ethylene vinyl acetate copolymers are employed wherein at least onecopolymer has a melt index in the range of about 20 to about 100 gramsper ten minutes, and another has a melt index in the range of about 300to about 400 grams per ten minutes. The foregoing melt indexes aredetermined using ASTM D1238, condition 190/2.16. Examples ofcommercially available ethylene-vinyl acetate copolymers that are usefulinclude Elvax 220 (a product of DuPont identified as having a melt indexof 150 and a vinyl acetate content of 28% by weight), Elvax 3185 (aproduct of DuPont identified as having a melt index of 43 and a vinylacetate content of 33% by weight), Elvax 3180 (a product of DuPontidentified as having a melt index of 25 and a vinyl acetate of 28% byweight), Ultrathene UE 654-35 (a product of Quantum Chemical identifiedas having a melt index of 48 and a vinyl acetate content of 33% byweight), Ultrathene UE 653-35 (a product of Quantum Chemical identifiedas having a melt index of 388 and a vinyl acetate content of 28% byweight), and Vynathene E 902-35 (a product of Quantum Chemicalidentified as having a melt index of 70 and a vinyl acetate content of40% by weight).

The ethylene-methyl acrylate copolymers (A)(ii) preferably have methylacrylate contents of up to about 40% by weight, more preferably about20% to about 40% by weight. The ethylene-ethylacrylate copolymerspreferably have ethyl acrylate contents of up to about 30% by weight,more preferably about 15% to about 30% by weight. The ethylene-acrylicacid and ethylene-methacrylic acid copolymers preferably have acrylicacid and methacrylic acid contents, respectively, of up to about 20% byweight, more preferably about 3% to about 20% by weight. Examples ofuseful ethylene-methacrylic acid copolymers include Nucrel 535 (aproduct of DuPont identified as having a melt index of 32 grams per tenminutes as determined by ASTM D1238, and a softening temperature of 75°C. as determined by ASTM D1525, rate B) and Nucrel 599 (a product ofDuPont identified as having a melt index of 500 grams per ten minutes asdetermined by ASTM D1238, and a softening temperature of 65° C. asdetermined by ASTM D1525, rate B).

The metal salts of ethylene-acrylic acid and ethylene-methacrylic acidthat are useful as copolymers (A)(ii) can be referred to as ionomers.These ionomers are typically neutralized salts of such copolymers, themetals preferably being sodium, lithium, barium, magnesium, zinc oraluminum, with sodium and zinc being particularly preferred.Commercially available ionomers that are useful are marketed by DuPontunder the trade name "Surlyn A".

The thermoplastic acrylic polymers A(iii) that are preferred for thepurposes of the present invention include homopolymers and copolymers ofacrylate eater monomers, for example, methyl acrylate, ethyl acrylate,methyl methacrylate, ethyl methacrylate, propyl acrylate, butylacrylate, ethylhexyl acrylate, butyl methacrylate, isobutyl methacrylateand the like. The acrylate copolymers may be derived from a minoramount, i.e., less than 40 percent by weight of the monomers, of amonomer other than an acrylate ester. The acrylate copolymer is derivedfrom a major amount, i.e., 60% by weight or greater of the total weightof the monomers, of at least one acrylate ester monomer. Among thepreferred other monomers, there may be mentioned styrene, acrylic acid,methacrylic acid, maleic anhydride, maleic acid, itaconic acid, alphamethyl styrene, and the like may be employed. The foregoing listing ofmonomers is provided for illustrative purposes only and it is notintended to be exhaustive of all possible monomers useful for thepreparation of the acrylic polymers. Examples of commercially availablethermoplastic acrylic polymers are acrylate copolymers available underthe ACRYLOID® Trademark (ACRYLOID® B-82 is a product of Rohm & Haas andis identified as an ethyl methacrylate copolymer having a glasstransition temperature (Tg) of 40° C.), NEOCRYL® solid acrylic resinswhich are products of ICI Resins U.S. and ELVACITE® which are also solidacrylic resins sold by DuPont. The thermoplastic acrylic polymeraccording to the present invention preferably has a glass transitiontemperature (Tg) of greater than 0° C. but less than 110° C.; morepreferably of greater than 10° C. but less than 100° C.; and mostpreferably of greater than 25° C. but less than 75° C. In other words,the thermoplastic acrylic polymers are formulated such that they havesufficient melt flow properties at the desired printing temperatures forthe coating compositions of the present invention.

The homopolymers (A)(i), copolymers (A)(ii) and thermoplastic acrylicpolymers (A)(iii) are preferably present in the inventive coatingcompositions at concentrations in the range of about 10% to about 50% byweight, more preferably about 15% to about 25% by weight based on thetotal weight of such coating compositions. Mixtures of one or morehomopolymers (A)(i) with one or more copolymers (A)(ii) and/or with oneor more thermoplastic acrylic polymers (A)(iii) are useful.

The thermoplastic polymeric material (B) may be any thermoplastic resinthat has a melting point in the range of about 0° C. to about 130° C.,more preferably about 60° C. to about 130° C., most preferably about100° C. to about 125° C., and is miscible/dispersible with the (A)polymer, e.g., an ethylene-vinyl acetate copolymer, used in accordancewith the invention. The thermoplastic material (B) can be athermoplastic resin that is modified by the addition of plasticizers orother conventional additives to achieve the desired melting point and/ormiscibility. Examples of useful thermoplastic resins include polyterpeneresins, aromatic-modified polyterpene resins, polyester derived frompentaerythritol and rosin acid, polystyrene, poly(alpha-methyl styrene),acrylonitrile-butadienestyrene, acetal, acrylic, cellulosic, chlorinatedpolyether, diallyl phthalate, phenoxy, polyamides, polycarbonates,polyethylene, polypropylene, polyvinylchloride, etc. Mixtures of two ormore of the foregoing resins can be used. Preferred resins arepolyterpene resins, aromatic-modified polyterpene resins, polyestersderived from pentaerythritol and rosin acid, polystyrene andpoly(alpha-methyl styrene). Examples of commercially availablethermoplastic materials that are useful include Zonarez 7110 (a productof Arizona Chemical identified as a polyterpene having a softening pointof 100° C.), Zonarez 7115 (a product of Arizona Chemical identified as apolyterpene having a softening point of 115° C.), Zonarez 7125 (aproduct of Arizona Chemical identified as a polyterpene having a meltingpoint of 125° C.), Piccolyte HM105 (a product of Hercules identified asan aromatic-modified terpene resin having a melting point of 105° C.),Kristalex 3100 (a product of Hercules identified as a poly(alpha-methylstyrene) having a melting point of 100° C.), and Sylvatac 115NS (aproduct of Arizona Chemical, Sylvachem Division, identified as apolyester derived from pentaerythritol and rosin acid having a softeningpoint of 110° C. and a molecular weight of about 1270). Thethermoplastic polymeric material (B) is preferably present in theinventive coating composition at a level in the range of about 35% toabout 65% by weight, more preferably about 40% to about 50% by weight.

The pigment (C) can be any pigment known in the art. Examples includetitanium dioxide, carbon black, chrome green, antimony yellow, antimonyorange, antimony oxide, iron oxide (natural or synthetic), cobalt blue,phthalo blue, phthalo green, azo red, diarylide yellow, etc. Mixtures oftwo or more of such pigments can be used. Pigment (C) is present in theinventive coating compositions at a sufficient level to provide thedesired degree of color and/or opacity. The amount of pigment isdependent upon the color shade desired. In one embodiment, pigment (C)is employed at a level in the range of about 1% to about 40% by weight,and in another embodiment it is employed at a level of about 5% to about25% by weight.

Wax (D) can be any wax having a melting point in the range of about 40°C. to about 110° C., more preferably about 60° C. to about 100° C. Theseinclude animal waxes such as beeswax, spermaceti, lanolin or shellacwax; vegetable waxes such as carnauba, candelilla, bayberry orsugarcane; mineral waxes such as ozocerite, ceresin or montan; petroleumwaxes such as paraffin, microcrystalline, petrolatum, slack wax or scalewax; synthetic waxes such as ethylenic polymers or polyol ether-esters(e.g., sorbitol and the Carbowax products of Union Carbide identified aspolyethylene glycols and methoxypolyethylene glycols); chlorinatednaphthalenes; hydrocarbon waxes made via Fischer-Tropsch synthesis. Wax(D) is preferably present in the inventive coating composition at alevel in the range of up to about 30% by weight, more preferably about2% to about 15% by weight.

The silicone polymers (E) contain repeating silicon-oxygen backbones andtypically have one or more organic groups attached to a significantproportion of the silicon atoms by silicon-carbon bonds. These organicgroups typically include methyl, longer chain alkyl groups (e.g., 2 toabout 7 carbon atoms), fluoroalkyl groups, phenyl, vinyl, etc. Thesilicon atoms can also have hydrogen, chlorine, alkoxy acyloxy, alkylamino groups, etc., attached thereto. These polymers include linear,branched and cross-linked structures. Examples of useful siliconepolymers include polydimethyl siloxane, polymethylvinyl siloxane,polymethylphenyl siloxane, polydiphenyl siloxane, etc. Copolymers madeby combining different siloxane units can be used. Examples includecopolymers of polydimethyl siloxane with polymethylvinyl siloxane,polymethylphenyl siloxane, polydiphenyl siloxane, etc. Mixtures of twoor more of these silicone polymers can be used. Examples of commerciallyavailable silicone polymers that are useful include those marketed byGeneral Electric under the trade designation SR882M. The siliconepolymers (E) are preferably present in the inventive coatingcompositions at a level in the range of up to about 5% by weight, morepreferably about 1% to about 2% by weight.

The fluorocarbon polymers (F) comprise polymers derived from monomerscontaining one or more atoms of fluorine or copolymers of such monomers,the fluorine-containing monomers being in the greatest mass. Examplesinclude polytetrafluoroethylene, fluorinated ethylene-propylene,polychlorotrifluoroethylene, polyvinylidene fluoride,polyhexafluoropropylene, etc. Mixtures of two or more of suchfluorocarbon polymers can be used. These fluorocarbon polymerspreferably have number average molecular weights in the range of aboutone million to about 20 million. The melting point of these fluorocarbonpolymers preferably ranges from about 450° F. to about 650° F., morepreferably about 550° F. to about 650° F. These fluorocarbon polymersare preferably present in the inventive coating compositions at a levelin the range of up to about 6% by weight, more preferably about 1% toabout 5% by weight, more preferably about 3.5% to about 4.5% by weight.

The plasticizer (G) is preferably a low-melting (i.e., meltingtemperature in the range of about 0° C. to about 50° C.) solid orliquid. Examples include aliphatic polymeric resins such as polybutene;and phthalate, adipate and sebacate esters of polyols such as ethyleneglycol and its derivatives, etc. Examples of commercially availableplasticizers that are useful include Hercoflex 500 (a product ofHercules identified as an aliphatic resin) and Indopol 14 (a product ofAmoco identified as a polybutene). The plasticizers (G) are preferablypresent in the inventive coating composition at a level of up to about10% by weight, more preferably about 1% to about 6% by weight.

The surfactants (H) are preferably of the nonionic type. Many suchsurfactants are known to the art. See, for example, McCutcheon's"Emulsifiers & Detergents", 1983, North American Edition, pp. 61-299,and International Edition, pp. 1-225, published by McCutcheon Division,MC Publishing Co., Glen Rock, N.J., U.S.A.; these pages beingincorporated herein by reference. These surfactants include the alkyleneoxide-treated products, such as ethylene oxide-treated phenols,alcohols, esters, amines and amides. Ethylene oxide-propylene oxideblock copolymers are also useful nonionic surfactants. Glycerol estersand sugar esters are also known to be nonionic surfactants. An exampleof a commercially available surfactant that is useful is Perenol GL12 (aproduct of Herkol identified as a mixed fatty acid ester). Many othersuitable nonionic surfactants are known; see, for example, theaforementioned McCutcheon's as well as the treatise "Non-IonicSurfactants" edited by Martin J. Schick, M. Dekker Co., New York, 1967,which is hereby incorporated by reference for its disclosures in thisregard. These surfactants are preferably employed at a sufficient levelto enhance the dispersion of the pigment (D) in the inventive coatingcomposition. The surfactant (H) is preferably employed in the inventivecoating composition at a level in the range of up to about 3% by weight,preferably about 1% to about 2% by weight.

The organo silanes (I) can be represented by the formula ##STR1##wherein R¹ is an alkoxy group of up to about 4 carbon atoms or anaryloxy group of up to about 10 carbon atoms; R² is an aliphatic or analicyclic group of up to about 8 carbon atoms or an aromatic group of upto about 12 carbon atoms; and m and n are independently numbers in therange of 1 to 3. R¹ can be methoxy, ethoxy, propoxy, butoxy, phenoxy,tolyloxy, xyloxy, etc. R² can be vinyl, propenyl, isopropenyl, acrylic,methacrylic, ethylacrylic, butenyl, isobutenyl, vinylene, benzyl,propylene-substituted benzyl, butylene-substituted benzyl,vinylene-substituted tolyl, methyl, ethyl, propyl, isopropyl, butyl,isobutyl, phenyl, benzyl, tolyl, xylyl, etc. Examples of useful silanesinclude gamma-methacryloxypropyltrimethoxysilane;3,4-epoxycyclohexylethyltrimethoxysilane; andgamma-glycidoxypropyltrimethoxysilane. These silanes are preferablypresent in the inventive coating compositions at levels of up to about3% by weight, more preferably about 0.5% to about 1% by weight.

An adhesion promoter (J) is optionally added to the composition of thepresent invention depending on the substrate to be coated or printed,the end use of the substrate or article and such other considerations.An adhesion promoter is preferably added to the coating composition whenthe substrate to be printed is glass. A preferred adhesion promotermaterial is a low molecular weight, non-reactive, epoxy resin capable ofmelt flow at the temperatures of printing. Exemplary of such materialsare epoxy resins sold under the trade name EPOTUFF® by ReicholdChemicals Inc.

The inventive coating compositions can include at least one dye. Any dyeknown in the art can be used, the particular dye and level of use beingdependent upon the desired color. Mixtures of two or more of such dyescan be used.

While the inventive coating compositions comprise basically thecomponents just described, it is understood that still other componentsmay be added in amounts as needed to modify the physical characteristicsof such compositions, such as flow properties, print definition, etc.,or reduce their cost. For example, particulate calcium carbonate and/orcolloidal silica may be incorporated as thixatropes or fillers.

The thermoplastic (A) and (B) polymers of the coating compositions ofthe present invention necessarily need to be capable of melt flow atprinting temperatures. Therefore, the combined (A) and (B) polymers musthave a minimal viscosity or flow upon heating to printing temperatureswhile not undergoing thermal degradation at these temperatures. Thecoating compositions of the present invention including the (A) and (B)polymers should generally be solid at or about room temperature and aliquid at about 200° F. to about 300° F. wherein the inventioncomposition exhibits a viscosity between about 5,000 cps to about100,000 cps at about 200° F. to about 300° F. and more preferably aviscosity of about 5,000 cps to about 80,000 cps at about 200° F. toabout 300° F. and most preferably a viscosity of about 10,000 cps toabout 50,000 cps at about 200° F. to about 300° F. An ideal viscosityfor the coating composition of the present invention is approximately18,000 cps at 260° F. For the purposes of the present invention, theviscosity for the compositions of the present invention was measured byusing ASTM D2196-86 modified by using a T-B spindle and a sampletemperature between 200° F. and 300° F.

The inventive coating compositions are preferably prepared by firstmelting the resin and wax components at a temperature in the range ofabout 80° C. to about 150° C., more preferably about 105° C. to about135° C. These materials are mixed with low-speed agitation on adisperser until homogeneous. The pigments and other additives, if used,are then introduced into the mixture with low-speed agitation. The speedof the disperser is then increased in order to disperse the pigment andadditive agglomerates. The mixture is then preferably agitated forapproximately one hour at a temperature of about 110° C. to about 150°C. The mixture is then cooled to solid form (preferably at a temperaturebelow about 40° C.) and packaged.

Application of the inventive coating compositions is preferably effectedby squeegeeing the coating composition through a heated screen of finemetal wires onto a substrate. Preferably the inventive coatingcompositions are heated to a temperature in the range of about 70° C. toabout 135° C., more preferably about 90° C. to about 120° C., prior toapplication to the substrate. The screen may be electrically heatedand/or the coating composition can be maintained fluid by radiantburners. The screen can be blocked or masked so that the coatingcomposition passing through the screen is applied to the substrate in apredetermined pattern. Various substrates of glass, ceramic, metal,plastic, fiberboard or textile, etc., may be coated or printed by thepresent process. Once applied to the substrate the coating compositionis preferably cooled to a temperature in the range of about 10° C. toabout 40° C. in preferably less than about one second. The ware beingprocessed can be in the form of bottles or tumblers. The inventivecoating compositions are particularly adapted for screen printingdisposable, throw-away containers, such as bottles or jars made ofglass, polyethylene, polypropylene, polyvinyl chloride, and the like.The applied coatings or prints can be subsequently polished by heatingthe applied coating or print to increase its gloss and/or smoothness,improve its adhesion to the substrate, and/or remove lingering solvents.Such heating can be effected by placing a flame over the applied coatingor print for a few seconds (e.g., about 2 to about 6 seconds) orsubjecting the applied coating or print to high-velocity hot air orradiant heat using known techniques.

In order to further illustrate the invention, the following examples ofpreferred formulations are provided. Unless otherwise indicated, in thefollowing examples as well as throughout the entire specification and inthe appended claims, all parts and percentages are by weight, and alltemperatures are in degrees centigrade.

EXAMPLE 1

    ______________________________________                                                             Parts/Wt.                                                ______________________________________                                        Zonarez 7115 (product of Arizona Chemical                                                            65                                                     identified as a polyterpene having                                            a melting point of 115° C.)                                            Elvax 220 (product of Dupont                                                                         20                                                     identified as an ethylene-vinyl-                                              acetate copolymer having a vinyl                                              acetate content of 28% by weight                                              and a melt index of 150)                                                      Titanium Dioxide       15                                                     ______________________________________                                    

EXAMPLE 2

    ______________________________________                                                             Parts/Wt.                                                ______________________________________                                        Zonarez 7125 (product of Arizona Chemical                                                            41.43                                                  identified as a polyterpene having                                            a melting point of 125° C.)                                            Ultrathene UE 654-35 (product of                                                                     12.43                                                  Quantum Chemical identified                                                   as an ethylene vinyl acetate copolymer                                        having a 33% by weight vinyl acetate                                          content and a melt index of 43)                                               Ultrathene UE 653-35 (product of                                                                     8.29                                                   Quantum Chemical identified                                                   as an ethylene vinyl acetate copolymer                                        having a 28% by weight vinyl acetate                                          content and a melt index of 388)                                              Ross Wax 100 (product of Frank B. Ross                                                               4.71                                                   Co., Inc. identified as a Fischer-                                            Tropsch wax having a congealing point                                         of 200-210° F. as determined by ASTM                                   D938)                                                                         Shamrock S195 (product of Shamrock                                                                   4.71                                                   Technologies identified as a poly-                                            ethylene wax having a melting point of                                        92° C.)                                                                General Electric SR882M (product of                                                                  1.13                                                   General Electric identified as a                                              silicone polymer)                                                             Shamrock SST2 (product of Shamrock                                                                   3.77                                                   Technologies identified as polytetra-                                         fluoroethylene)                                                               Titanium Oxide, as a pigment                                                                         23.53                                                  ______________________________________                                    

EXAMPLE 3

    ______________________________________                                                             Parts/Wt.                                                ______________________________________                                        Acryloid B-72 (product of Rohm & Haas,                                                               30                                                     identified as an ethyl methacrylate                                           copolymer with a glass transition                                             temperature of 40° C.)                                                 Piccolastic A-75 (product of Hercules, Inc.,                                                         40                                                     identified as a polystyrene of low                                            molecular weight, 300-400, and a                                              softening point of about 75° C. by the                                 ring and ball method)                                                         Piccolastic A-5 (product of Hercules, Inc.,                                                          10                                                     identified as a polystyrene of low                                            molecular weight, 300-400, and a                                              softening point of about 5° C. by                                      the ring and ball method)                                                     Aerosil R-972 (product of Degussa,                                                                   2                                                      identified as a fumed silica)                                                 Titanium Dioxide, as a pigment                                                                       18                                                     ______________________________________                                    

EXAMPLE 4

    ______________________________________                                                             Parts/Wt.                                                ______________________________________                                        B-82 Acrylic (A product of Rohm                                                                      20                                                     and Haas identified as a                                                      methyl methacrylate copolymer                                                 with a glass transition                                                       temperature (Tg) of 35° C.)                                            Epotuff 37-002 (product of Reichold                                                                  20                                                     Chemicals Inc., identified as a                                               nonreactive, low molecular weight                                             epoxy resin and melting point of                                              220° C.)                                                               Piccolastic A-75 (product of Hercules, Inc.,                                                         20                                                     identified as a polystyrene of low                                            molecular weight, 300-400, and a                                              softening point of about 75° C. by the                                 ring and ball method)                                                         Piccolastic A-5 (product of Hercules, Inc.,                                                          20                                                     identified as a polystyrene of low                                            molecular weight, 300-400, and a                                              softening point of about 5° C. by                                      the ring and ball method)                                                     Titanium Dioxide       15                                                     Aerosil R-972 (product of Degussa,                                                                   2                                                      identified as a fumed silica)                                                 DC-200 (product of Dow)                                                                              1                                                      Shamrock SST2 (product of Shamrock                                                                   2                                                      Technologies identified as polytetra-                                         fluoroethylene)                                                               ______________________________________                                    

EXAMPLE 5¹

    ______________________________________                                                             Parts/Wt.                                                ______________________________________                                        B-82 Acrylic (A product of Rohm                                                                      20                                                     and Haas identified as a                                                      methyl methacrylate copolymer                                                 with a glass transition                                                       temperature (Tg) of 35° C.)                                            Epotuff 37-002 (product of Reichold                                                                  20                                                     Chemicals Inc., identified as a                                               nonreactive, low molecular weight                                             epoxy resin and melting point of                                              220° C.)                                                               Piccolastic A-75 (product of Hercules, Inc.,                                                         20                                                     identified as a polystyrene of low                                            molecular weight, 300-400, and a                                              softening point of about 75° C. by the                                 ring and ball method)                                                         Piccolastic A-5 (product of Hercules, Inc.,                                                          25                                                     identified as a polystyrene of low                                            molecular weight, 300-400, and a                                              softening point of about 5° C. by                                      the ring and ball method)                                                     PC 9673 deep red (Daniels)                                                                           5                                                      Aerosil R-972 (product of Degussa,                                                                   3                                                      identified as a fumed silica)                                                 Titanium Dioxide       1                                                      DC-200 (product of Dow)                                                                              1                                                      Shamrock SST2 (product of Shamrock                                                                   2                                                      Technologies identified as polytetra-                                         fluoroethylene)                                                               Red Iron Oxide 297 (product of Columbian                                                             3                                                      Chemical)                                                                     ______________________________________                                         .sup.(1) The color of the composition is very close to Ceramic "Parisian      Red".                                                                    

EXAMPLE 6

A piece of glassware is printed with the composition of Example 2according to the following process.

1) Melt the thermoplastic polymeric material at a temperature of between200° F. to about 300° F.

2) Place a small amount of melted material onto an electrically heatedwire screen. (100-325 U.S. mesh) This screen is masked such that thecoating will be deposited as a design on the ware.

3) The ware is decorated by pushing the heated thermoplastic polymericmaterial through the screen, (at temperatures of about 180° F. to about300° F.) by means of a squeegee.

4) The heated material will immediately "freeze" on the relatively coolware allowing successive colors to be applied.

5) The decorated ware is then heated to a temperature of between 250° F.to 500° F. to allow it to reflow and obtain a glossy surface and betteradhesion.

6) The ware is allowed to cool and is removed from the production linefor storage or shipment.

While the invention has been explained in relation to its preferredembodiments, it is to be understood that various modifications thereofwill become apparent to those skilled in the art upon reading thespecification. Therefore, it is to be understood that the inventiondisclosed herein is intended to cover such modifications as fall withinthe scope of the appended claims.

What is claimed is:
 1. A printing coating composition for forming adecorative coating on a substrate comprising:(A) (i) at least onehomopolymer of ethylene having a melt index of at least about 220 gramsper ten minutes as determined by ASTM D1238, condition 190/2.16, or (ii)at least one copolymer of ethylene and a second ethylenicallyunsaturated monomer having a melt index of at least about 20 grams perten minutes as determined by ASTM D1238, condition 190/2.16, or (iii) atleast one thermoplastic acrylic homopolymer or copolymer having a glasstransition temperature (Tg) of greater than 0° C. but less than 110° C.,or (iv) a mixture of (i), (ii) and (ii); (B) at least one thermoplasticpolymeric material different than (A) having a melting point in therange of about 0° C. to about 130° C. and being dispersible with (A)wherein the polymer composition of (A) and (B) is normally solid at roomtemperature but is a viscous liquid at about 200° F. to about 300° F.having a viscosity in the range of about 5,000 cps to about 100,000 cps;and (C) an adhesion promoter, said adhesion promoter comprising an epoxyresin.
 2. The composition of claim 1 wherein said adhesion promotor (C)is a low molecular weight epoxy adhesion promoter.
 3. A substantiallysolvent-free printing coating composition for forming a decorativecoating on a substrate comprising:(A) at least one copolymer of ethyleneand a second ethylenically unsaturated monomer having a melt index of atleast about 20 grams per ten minutes as determined by ASTM D1238,condition 190/2.16; (B) at least one thermoplastic polymeric materialdifferent than (A) having a melting point in the range of about 0° C. toabout 130° C. and being dispersible with (A) wherein the polymercomposition of (A) and (B) is normally solid at room temperature but isa viscous liquid at about 200° F. to about 300° F. having a viscosity inthe range of about 5,000 cps to about 100,000 cps; (C) an adhesionpromoter, said adhesion promoter comprising an epoxy resin; and (D) atleast one pigment.